Emerson 480V Manuel D’Utilisation

The UPS requires both power and control cabling once it has been mechanically installed. All control 

cables must run separate from power cables in metal conduits or metal ducts that are electrically 

bonded to the metalwork of the cabinets to which they are connected.

The main factors affecting the choice and size of cable are voltage, current (also taking into account 

overcurrent), room temperature and conditions of installation of the cable.
The power cables of the system must be sized with respect to the following description:

• UPS input cables - The UPS input cables must be sized for the maximum input current, includ-

ing the maximum battery recharge current, given in Table 8, with respect to the unit rating and 

the input AC voltage.

• UPS bypass and output cables - The bypass and output cables must be sized for the nominal 

output current, given in Table 8, with respect to the unit rating and the output AC voltage.

• Battery cables - When connecting an external battery cabinet, the battery cables must be sized 

for the battery discharge current at the end-of-discharge voltage, as given in Table 8, with 

respect to the unit rating.

The power cables can be sized to suit the UPS unit rating according to Table 8.

Refer to Table 24 for lug size and torque requirements.

Before connecting input power to the Liebert NX, ensure that you are aware of the location 

and operation of the overcurrent protection devices that connect the UPS input/bypass supply 

to the power distribution panel.
De-energize and lockout or tagout all incoming high- and low-voltage power circuits before 

installing cables or making any electrical connections.

NOTE
Table 8 gives nominal currents for determining the size of UPS power cables. Other important 

NOTE
When installing a Liebert NX with Softscale